"Biographer Donald H. Wolfe in The Last Days of Marilyn Monroe, writes his belief that Norma Jeane's biological father was Charles Stanley Gifford, a salesman for RKO Pictures where Gladys worked as a film editor. Her birth certificate lists Gladys's second husband, Martin Edward Mortensen, as the father. Although Mortensen separated from Gladys before her daughter's birth, some biographers speculate he may have been the father.[10] In an interview with Lifetime, James Dougherty, Monroe's first husband, said Norma Jeane believed that Gifford was her father. Whoever the father was, he played no further part in Monroe's life."